An end-user license agreement (EULA) is a legal contract entered into between a software developer or vendor and the user of the software, often where the software has been purchased by the user from an intermediary such as a retailer. A EULA specifies in detail the rights and restrictions which apply to the use of the software.[1]

Many form contracts are only contained in digital form, and only presented to a user as a click-through which the user must "accept". As the user may not see the agreement until after he or she has already purchased the software, these documents may be contracts of adhesion.

Software companies often make special agreements with large businesses and government entities that include support contracts and specially drafted warranties.

Some end-user license agreements accompany shrink-wrapped software that is presented to a user sometimes on paper or more usually electronically, during the installation procedure. The user has the choice of accepting or rejecting the agreement. The installation of the software is conditional to the user clicking a button labelled "accept". See below.

Many EULAs assert extensive liability limitations. Most commonly, an EULA will attempt to hold harmless the software licensor in the event that the software causes damage to the user's computer or data, but some software also proposes limitations on whether the licensor can be held liable for damage that arises through improper use of the software (for example, incorrectly using tax preparation software and incurring penalties as a result). One case upholding such limitations on consequential damages is M.A. Mortenson Co. v. Timberline Software Corp., et al.[citation needed] Some EULAs also claim restrictions on venue and applicable law in the event that a legal dispute arises.

Some copyright owners use EULAs in an effort to circumvent limitations the applicable copyright law places on their copyrights (such as the limitations in sections 107–122 of the United States Copyright Act), or to expand the scope of control over the work into areas for which copyright protection is denied by law (such as attempting to charge for, regulate or prevent private performances of a work beyond a certain number of performances or beyond a certain period of time). Such EULAs are, in essence, efforts to gain control, by contract, over matters upon which copyright law precludes control.
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This kind of EULAs concurs in aim with DRM and both may be used as alternate methods for widening control over software.

In disputes of this nature in the United States, cases are often appealed and different circuit courts of appeal sometimes disagree about these clauses. This provides an opportunity for the U.S. Supreme Court to intervene, which it has usually done in a scope-limited and cautious manner, providing little in the way of precedent or settled law.[citation needed]

End-user license agreements are usually lengthy, and written in highly specific legal language, making it difficult for the average user to give informed consent[3]. If the company designs the end-user license agreement in a way that intentionally discourages users from reading them, and uses difficult to understand language, many of the users may not be giving informed consent.

A free software license grants users of that software the rights to use for any purpose, modify and redistribute creative works and software, both of which are forbidden by the defaults of copyright, and generally not granted with proprietary software. These licenses typically include a disclaimer of warranty, but this feature is not unique to free software.
[4]Copyleft licenses also include a key addition provision that must be followed in order to copy or modify the software, that requires the user to provide source code for the work and to distribute their modifications under the same license (or sometimes a compatible one); thus effectively protecting derivative works from losing the original permissions and being used in proprietary programs.

Unlike EULAs, free software licenses do not work as contractual extensions to existing legislation. No agreement between parties is ever held, because a copyright license is simply a declaration of permissions on something that otherwise would be disallowed by default under copyright law.[2]

The term shrink-wrap license refers colloquially to any software license agreement which is enclosed within a software package and is inaccessible to the customer until after purchase. Typically, the license agreement is printed on paper included inside the boxed software. It may also be presented to the user on-screen during installation, in which case the license is sometimes referred to as a click-wrap license. The inability of the customer to review the license agreement before purchasing the software has caused such licenses to run afoul of legal challenges in some cases.

Whether shrink-wrap licenses are legally binding differs between jurisdictions, though a majority of jurisdictions hold such licenses to be enforceable. At particular issue is the difference in opinion between two US courts in Klocek v. Gateway and Brower v. Gateway. Both cases involved a shrink-wrapped license document provided by the online vendor of a computer system. The terms of the shrink-wrapped license were not provided at the time of purchase, but were rather included with the shipped product as a printed document. The license required the customer to return the product within a limited time frame if the license was not agreed to. In Brower, New York's state appeals court ruled that the terms of the shrink-wrapped license document were enforceable because the customer's assent was evident by its failure to return the merchandise within the 30 days specified by the document. The U.S. District Court of Kansas in Klocek ruled that the contract of sale was complete at the time of the transaction, and the additional shipped terms contained in a document similar to that in Brower did not constitute a contract, because the customer never agreed to them when the contract of sale was completed.

Further, in ProCD v. Zeidenberg, the license was ruled enforceable because it was necessary for the customer to assent to the terms of the agreement by clicking on an "I Agree" button in order to install the software. In Specht v. Netscape Communications Corp., however, the licensee was able to download and install the software without first being required to review and positively assent to the terms of the agreement, and so the license was held to be unenforceable.

Click-wrap license agreements refer to website based contract formation (see iLan Systems, Inc. v. Netscout Service Level Corp.). A common example of this occurs where a user must affirmatively assent to license terms of a website, by clicking "yes" on a pop-up, in order to access website features. This is therefore analogous to shrink-wrap licenses, where a buyer implied agrees to license terms by first removing the software package's shrink-wrap and then utilizing the software itself. In both types of analysis, focus is on the actions of end user and asks whether there is an explicit or implicit acceptance of the additional licensing terms.

Most licenses for software sold at retail disclaim (as far as local laws permit) any warranty on the performance of the software and limit liability for any damages to the purchase price of the software. One well-known case which upheld such a disclaimer is Mortenson v. Timberline .

Jerry Pournelle wrote in 1983, "I've seen no evidence to show that ... Levitical agreements — full of "Thou Shalt Nots" — have any effect on piracy". He gave an example of an EULA that was impossible for a user to comply with, stating "Come on, fellows. No one expects these agreements to be kept". Noting that in practice many companies were more generous to their customers than their EULAs required, Pournelle wondered "Why, then, do they insist on making their customers sign 'agreements' that the customer has no intention of keeping, and which the company knows won't be kept? ... Must we continue making hypocrites out of both publishers and customers?"[14]

One common criticism of end-user license agreements is that they are often far too lengthy for users to devote the time to thoroughly read them. In March 2012, the PayPal end-user license agreement was 36,275 words long[15] and in May 2011 the iTunes agreement was 56 pages long.[16] News sources reporting these findings asserted that the vast majority of users do not read the documents because of their length.

Several companies have parodied this belief that users do not read the end-user-license agreements by adding unusual clauses, knowing that few users will ever read them. As an April Fool's Day joke, Gamestation added a clause stating that users who placed an order on April 1, 2010 agreed to irrevocably give their soul to the company, which 7,500 users agreed to. Although there was a checkbox to exempt out of the "immortal soul" clause, few users checked it and thus Gamestation concluded that 88% of their users did not read the agreement.[17] The program PC Pitstop included a clause in their end-user license agreement stating that anybody who read the clause and contacted the company would receive a monetary reward, but it took four months and over 3,000 software downloads before anybody collected it.[18] During the installation of version 4 of the Advanced Query Tool the installer measured the elapsed time between the appearance and the acceptance of the end-user license agreements to calculate the average reading speed. If the agreements were accepted fast enough a dialog window “congratulated” the users to their absurdly high reading speed of several hundred words per second.[19]South Park parodied this in the episode "HumancentiPad", where Kyle had neglected to read the terms of service for his last iTunes update and therefore inadvertently agreed to have Apple employees experiment upon him.[20]

End-user license agreements have also been criticized for containing terms that impose onerous obligations on consumers. For example, Clickwrapped, a service that rates consumer companies according to how well they respect the rights of users, reports that they increasingly include a term that prevents a user from suing the company in court.[21]

In a recent article published by Kevin Litman-Navarro for the New York Times, titled We Read 150 Privacy Policies. They Were an Incomprehensible Disaster[22], the complexity of 150 terms from popular sites like Facebook, Airbnb, etc. were analyzed and comprehended. As a result, for example, the majority of licenses require college or higher-level degrees: "To be successful in college, people need to understand texts with a score of 1300. People in the professions, like doctors and lawyers, should be able to understand materials with scores of 1440, while ninth graders should understand texts that score above 1050 to be on track for college or a career by the time they graduate. Many privacy policies exceed these standards."[22]